Democrats are on the defensive as it gets closer to the midterm elections. We're watching primary results tonight in four states - Minnesota, Wisconsin, Connecticut and Vermont. A campaign in Minnesota has been rocked in recent days with allegations of domestic violence against Congressman Keith Ellison. Whether he wins or loses the primary for state attorney general, those questions could persist since he is also a leader in the Democratic National Committee.

With more on that and other primaries being decided tonight, we're joined by NPR lead political editor Domenico Montanaro. Welcome to the studio.

DOMENICO MONTANARO, BYLINE: Hey there, Audie.

CORNISH: There are a lot of races to sort through. We're going to start in Minnesota and with those allegations against Ellison. What more have you learned?

MONTANARO: You know, well, what we know here is that the son of former Ellison - of a former Ellison girlfriend wrote a Facebook post three days ago saying that he has seen a video showing Ellison dragging his mother off the bed by her feet, yelling and cursing at her to get out of the house. The former girlfriend, Karen Monahan, has tweeted that everything her son said is true, but she's so far declined to release the video because she said it's humiliating and traumatizing.

Ellison himself is not only a congressman but vice chairman of the Democratic National Committee. He vehemently denies the allegations. He confirmed in a statement that he had a long-term relationship with Monahan but that the video does not exist, he said, because I never behaved this way, and any characterization otherwise is false.

CORNISH: What has the DNC said so far about these allegations?

MONTANARO: I reached out to the DNC this afternoon, and they got back to me and said, these allegations recently came to light, and we are reviewing them. All allegations of domestic abuse are disturbing and should be taken seriously. Now, that came after I spoke with the former communications director at the DNC, Luis Miranda, who told me, quote, "the party has no choice but to suspend him at a minimum until they figure out what's going on." Frankly, it would be malpractice, he said, not to. We've made it clear we're going to take these accusations seriously at a minimum, is what that would say, and he said that we set too high a standard not to take this seriously.

And look; this reflects a lot of what I've heard from Democratic strategists this afternoon who said that they think these allegations have to be taken seriously but that some in the party have actually grown a little bit skittish after the response to Senator Al Franken, who was let go. And some people didn't feel within the party that he was treated fairly.

CORNISH: On the Republican side of things, where are they eyeing opportunities to make gains?

MONTANARO: Right. Well, this has been a year where we've talked a lot about potential Democratic gains. But tonight will set up potentially competitive governor's races in Minnesota and Connecticut. Republicans think they have a shot in both of those states. And there are two House seats in Minnesota where the Democrats have decided to seek other office rather than face re-election. Trump, we should point out, won those districts in 2016, which has showed that Minnesota is trending Republican overall much more so in recent elections. Trump only lost the state by two points overall.

CORNISH: And Wisconsin - it was reliably Democratic, but President Trump flipped it in 2016. I understand Republican Governor Scott Walker is going for a third term. What can you tell us? What's going on there?

MONTANARO: You know, he's not necessarily in great shape. The people in the state are split on the job he's doing. His poll numbers have kind of been static for the past six months or so. And Trump's poll numbers here and in other Midwestern states have shown him faring worse than during the 2016 election - so still very much a swing state. Democrats are more fired up this year. And what's interesting is Walker really hasn't been on the ballot when the winds were blowing against his party as he is this year.

CORNISH: Finally, in Vermont - people are paying attention to races there as well. What's happening?

MONTANARO: Well, the Republican governor, Phil Scott, was thought to be in pretty good shape, but his poll numbers have dropped significantly since signing a gun control measure into law. One of the people on the ballot on the Democratic side to pay attention to is Christine Hallquist. She's transgender and is a former energy company executive. If she wins, she'd be the first transgender candidate to win a major party nomination for governor ever.

By the way, someone else on the ballot that's interesting to watch is Ethan Sonneborn. He's just 14. He can't even vote for himself. But he is allowed to be on the ballot because there's no age requirement to run for governor of Vermont. And if he does win, the secretary of state's office tells me he would be allowed to serve - so definitely someone to watch maybe not tonight but in the future.